It reads completed outgoing stock moves with a delivery address that has a country. Check that: deliveries are validated, the customer has a country set, and the window (Looking Back To) covers when you shipped.
Either no regime is seeded for that country, or the regime is sub-national and the delivery address has no state set. US and Canadian jurisdictions only match shipments to the specific state or province.
Read the confidence rating and open the Missing Data tab. Products shipped without a packaging specification are listed there with their volumes; they are not counted as zero, they are counted as unknown.
Three things to check, in order:
Check the unit on the component. Weights are entered in g, kg, oz or lb and normalised to grams; the normalised figure is shown read-only beside the entry.
It has not been verified against its source within twelve months, or was seeded without a verification date because we inferred it. Open it, check the source URL, correct the date if needed and set Verified On. This is expected on some records and is deliberate: an unchecked date should nag somebody rather than sit there looking authoritative.
They are only created for markets you are registered in or that the latest assessment found. Run the radar, or add the registration.
It cannot be recomputed - that is deliberate, so the filed figure stays what you filed. Duplicate it, correct the underlying data, and compute the copy.